Question: I know you said that scales are for "idiots" but what about scales that figure body fat percentage/composition? How do they work and do they really work? Or are these scales for idiots, too? And if they're not a big scam, what are good things to search for when purchasing one? Thanks a bunch!
Answer: Scales are for idiots because most people on a fat loss program look too often to the scale for their progress. If you are in a fat loss program that combines exercise and sensible eating then the scale is not an accurate measure of progress. With that said, I am for measuring body fat to lean mass ratio and most body fat scales do that to some extent. Most body fat scales such as Tanita® use a technology called Bioelectrical Impedance.
A completely harmless electrical current is passed through your body, usually your legs. The electrical current passes more quickly through fat free tissue like muscle than it does through fat or bone tissue. The amount of resistance to the electrical current relates to how much fat-free mass a person has on their body.
Like all body fat tests, body fat scales don't actually measure your body fat percentage. They measure your body density, the scale then uses a formula to calculate body fat percentage based on your body density.
Unfortunately, there is no one formula that accurately predicts body fat for everyone. Differences in age, gender, ethnicity, body size and fitness level can have a significant affect on the results.
Most scales can account for some of the basic differences such as age and gender, but take the actual body fat percentage they give you as just a number and thats all. Whether body fat scales measure your exact body fat percentage or not doesn't really matter! As long as they can accurately show changes in your body composition over time, that's all you need. The real trick is to just be consistent with your monitoring. If you step on the scale naked at 7:30 am the first time then every time after that you must step on the scale at 7:30am in your birthday suit.
Is it the best way? I really cant say, but it is a way to help measure progress. I personally like a tape measure and a photograph, but thats me.